Francys K. V. Moreira, Ph.D.National Nanotechnology Laboratory for Agribusiness (LNNA)

Embrapa Instrumentation, São Carlos (SP), Brazil

Continuous casting: a soft processing approach to fabricate polysaccharide-based bioplastics

Biopolymers & Bioplastics-2015 “Bio World Innovation: Smart, green and environmentally sustainable biopolymers

BackgroundNon-biodegradable plastics – Versatile

materials

Images from Internet.

BackgroundNon-biodegradable plastics – The

“dark side”

Images from Internet.

Background

4

Celullose

Chitin

Pectins

Hemicelluloses

Starch

Carragenan

Alginates

Polysaccharides

Green raw-materials for

plastic production

BackgroundConsiderable potential for short time

applications

Biodegradable plastic

wraps

Edible films

Fully biodegrada

bleRelatively cheap

Neutral and hydro-soluble Abundant as a natural

resourceImages from Internet.

Background

Blow Molding Extrusion Single Screw Extrusion Twin Screw Extrusion Fiber Spinning Dry Spinning Melt Spinning Wet Spinning Filament Winding Film Blowing Injection Molding Mixing and Compounding Batch Intensive Mixing Twin Screw Extrusion Pultrusion Reaction Injection Molding Spin Coating Transfer Molding.

*http://www.polymerprocessing.com/operations/index.html

Polymer Processing Methods

Images from Internet.

BackgroundCasting as a processing method for biodegradable polymers

BackgroundCasting is not applicable to large scale production

Blow Molding Extrusion Fiber Spinning Mixing and Compounding Pultrusion Transfer Molding

Injection molding.

Casting

Image from Internet.

CONTINUOUS CASTING AS A SCALABLE-UP METHOD FOR POLYSACCHARIDE FILM PRODUCTION

Background

Low temperatures involved (90 °C);Precise control of film thickness;Short time-related process (4 min);Applicable for industrial production of biodegradable films.

CONTINUOUS CASTING

To determine the suitability of the continuous casting as a processing method for the production of bioplastic films from polysaccharides.

GENERAL OBJECTIVE

Study of different

polysaccharides;

Rheology of

polysaccharide

solutions;

Delineation of

processing conditions;

Mechanical

characterization.

Sample* Concentration range (wt.%)

Pectin 4 - 10

Chitosan 5 - 8

Hydroxypropyl Methyl-cellulose (HPMC) 4 - 12

Carboxymethyl-cellulose (CMC) 1-2

Corn starch 4-10

Alginate_Na+ 1 - 5

Carragenan 1-4

Experimental – Polysaccharide samples

*HPMC: Methocel E19FG (Dow); Pectin: Citrus Pectin USP-B (CKPelco); Chitosan (Polymar); CMC: Murta Ing.; Starch: CascoTM (Ingredion); Alginate: (GastronomyLab): Carragenan GENUGEL® (CPKelco)

Aqueous polysaccharide solutions used in the CC.

Experimental – Labcoater casting unit*

*KTF Devices: (1) – Substrate roll; (2) Foulard of Transport; (3) Coating device; (4) IR pre-dryer; (5) First hot air drying chamber; (6) Foulard of lamination; (7) Lamination roll; (8) Second hot air drying chamber; (9) Collecting roll.

ExperimentalMathis KTF-B Coating Device

2 - Doctor Knife Type B

1 - Substrate

3 - Comparative

clocks (± 0.001 mm)

Continuous casting - Step 1: Casting

Continuous casting - Step 1: Casting

Continuous casting - Step 2: Drying

Continuous casting - Step 3: Rolling up

CONTINUOUS CASTING

- HIGHLIGHTED RESULTS-

HIGHLIGHTED RESULTS

Rheological Aspects

IDEAL UNDESIRABLEUNDESIRABLE

Low viscosity High viscosity Too high viscosity

Molecular mass, Solid content

HPMC 2 wt.% PEC 8 wt.% CMC 2 wt.%

LiquidLiquid Gel

HIGHLIGHTED RESULTSRheological Aspects

-20 -10 0 10 20 30 40 50 60 70 80 90 100 110

0

2

4

6

8

10

12

2 wt.%4 wt.%

6 wt.%

10 wt.%

Vis

cosi

ty (P

a s)

Shear rate (s-1)

HPMC 12 wt.%

Flow curves (25 °C) of aqueous HPMC solutions with different concentrations.

IDEAL

-20 -10 0 10 20 30 40 50 60 70 80 90 100 110

0

20

40

60

80

100

120

HPMC 12 wt.%

PEC 8 wt.%

Vis

cosi

ty (P

a s)

Shear rate (s-1)

Rheological Characterization

HIGHLIGHTED RESULTS

Comparison of flow curves (25 °C) between a HPMC solution (12 wt.%) and pectin solution (8 wt.%)

0 100 200 300 400 500-200

0

200

400

600

800

1000

1200

1400

1600

1800

G''>>G'

HPMC 12 wt.%

Loss modulus, G''

Mod

ulus

(P

a)

Angular frequency (rad s-1)

Storage modulus, G'

HIGHLIGHTED RESULTSRheological Characterization

Frequeny sweep at 25 °C: Dependence of storage modulus (G’) and loss modulus (G’’) on the angular frequence for an aqueous HPMC solution (12 wt.%).

HIGHLIGHTED RESULTS

Sample Concentration (wt.%)

Temperature (°C)

Processing speed*

(m min-1)

Film thickness

(μm)**

Coef. Of variation

(%)***

Pectin 8 130 0.15 14 - 50 4

Chitosan 5 120 0.15 15 - 80 9

HPMC 12 130 0.12 30 - 100 8

CMC 1.55 140 0.08 20 - 40 18

Starch 5 100 0.12 20 - 30 9

Alginate 1.5 - 2 140 0.08 20 - 40 17

Carragenan 2 140 0.08 20 - 40 17

Summary of the best CC conditions for some polysaccharides

*Maximum value; ** Wet solution layer thickness = 0.05 - 0.2 mm;***n = 10.

HIGHLIGHTED RESULTSMechanical Characterization

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34

0

5

10

15

20

25

30

35

40

0.20 mm

0.125 mm

0.1 mm

0.175 mm

For

ce (N

)

Deformation (mm)

Chitosan, 5 wt.%, Acetic acid 2 v.%

0.150 mm

Force (N) – deformation (mm) curves of chitosan films with varying thickness.

19 μm

25 μm

34 μm

45 μm

42 μm

HIGHLIGHTED RESULTSSummary of Mechanical Properties*

Polymer Elastic Modulus (MPa)

Tensile Strength (MPa)

Elongation at Break (%)

Pectin 3000 - 4000 20 - 100 2 - 4

Chitosan 1900 - 3000 20 - 50 2 - 18

HPMC 1500 - 2000 30 – 40 4 - 10

CMC 1000 - 1200 6 – 17 6 - 20

Starch 1000 - 1200 15 - 20 2 - 5

LLDPE** 130 - 520 9 – 20 100 - 1200

LHDPE** 60 - 290 10 - 60 N.D.

Data were collected following the ASTM D 882 protocol, cross-head speed of 10 mm min-1* , load cell of 10 Kgf. A. Prasad, Polymer Data Handbook, J. E. Mark, Ed. Oxford University Press, Oxford, 1999, 524.

Concluding Remarks

Continuous casting could be a suitable method for the production of bioplastic films at large scale from any type of polysaccharide;

Homogeneous polysaccharide film sheets can be properly fabricated only from liquid- or weak gel-like formulations. Formulations with high solid content are always desirable;

The mechanical parameters of the polysaccharide-based bioplastic films can be easily tuned by setting the thickness during the continuous casting process.

CONTINUOUS CASTING

- OUTLOOKS-

POLYMER PROCESSING OF DELICATE COMPOUNDS

Dr. Tara McHugh, leading scientist in fruit puree edible films for food packaging (WRRC-ARS/USDA).

POLYMER PROCESSING OF DELICATE COMPOUNDS

Nori

Watermelon

Passion fruit

Red guava

ASTM-D638 Type I specimens for red guava, passion fruit, and watermelon-based bioplastics.

INTENSIFICATION OF BIONANOCOMPOSITES’

PROPERTIES

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.50

10

20

30

40

50

60

70

80

Tens

ile S

treng

th (M

Pa)

Mg0.75

Al0.25

(OH)2 (wt.%)

Bench Labcoater

Tensile strength evolution of pectin-hydrotalcite bionanocomposites made by continuous (CC) and bench (BC) casting. Tensile tests were carried out using an Instron Machine at speed of 25

mm min-1.*

Bench casting vs. continuous casting

*Moreira, F. K. V., Materials Science and Engineering. Thesis (2014), Federal University of São Carlos, Brazil

Luiz H. C. Mattoso

Tara McHugh

Don Olson

Roberto Bustillos

Caio Gomide

Marcos Lorevice

Acknowledgments

Scientific Staff

Contacts: Francys Moreira (moreira.fkv@gmail.com)

Financial Support

EMBRAPA

FAPESP (Project no 2012/87216-0)

FINEP/MCT

CNPq (CNPq/Sisnano 402287/2013-4)

CAPES